Boom type cranes



Feb. 20, 1968 R. 6. LE TOURNEAU BOOM TYPE CRANES Original Filed Jan. 27, 1965 INVENTOR. %0%em 5%? wmew United States Patent 3,369,670 BOOM TYPE CRANES Robert G. LeTourneau, P.O. Box 2307, Lougview, Tex. 75601 Continuation of application Ser. No. 428,378, Jan. 27, 1965. This application Apr. 25, 1967, Ser. No. 640,433 3 Claims. (Cl. 212-55) ABSTRACT OF THE DISCLOSURE A crane having a boom mounted for powered reciprocable movement at the outer region of a support structure which in turn is pivotally mounted at the inner region for powered movement about a horizontal axis, with the support structure being mounted on a base member structure which extends upwardly and outwardly from a pedestal turntable. The base memberis capable of limited movement relative to the turntable to reduce the overall crane height when stowed for transportation.

This is a continuation of application Ser. No. 428,378 filed January 27, 1965 now abandoned.

My invention relates in general to cranes and in particular to an improved boom type crane and the mechanism used to manipulate the boom.

Cranes of the type that utilize a boom for lifting and transferring selected articles need a long boom if the articles are to be transferred to or from a high elevation. If the articles are heavy, however, the stresses become quite large in a long boom. As a consequence, various arrangements have been devised for adjusting the length of the boom to decrease the stresses when heavy articles are lifted.

A typical prior art adjustable length boom is one that telescopes. Although such booms are commonly used, they nevertheless have a number of disadvantages. For one thing, if only one telescopic section is used, the boom can only be shortened to a length not less than one half its original length. On the other hand, if a number of telescoping sections are provided, the reliability of the mechanism is decreased due to the increased number of parts.

Another disadvantage of prior art adjustable booms is that shortening the length of the boom decreases rather severely the elevation to which the articles may be raised. That is, if the boom length is shortened by a factor of two, then the maximum elevation of the boom is also shortened by a factor of about'two.

The general object of my invention is to provide an improved boom type crane.

Another object of my invention is to provide an improved crane wherein the boom is attached thereto in a manner that enables the lifting of heavy articles to a high elevation while keeping the stresses of the boom to a minimum.

Another object of my invention is to provide a boom type crane with an improved apparatus for pivotally moving the boom with respect 'to its supporting base.

These and other objects are elfected by my invention as will be apparent from the following description taken in accordance with the accompanying drawing, forming a part of this application, in which:

FIG. 1 is a schematic side elevational view that illustrates a crane of the boom type that embodies the principles of my invention;

FIG. 2 is another schematic side elevational view showing the crane of FIG. 1 with its supporting mechanism lowered to facilitate the transportation of the crane from one location to another;

ice

FIG. 3 is a side elevational view of a pedestal turntable upon which the supporting mechanism for the boom is mounted;

FIG. 4 is a front elevational view of the pedestal turntable shown in FIG. 3;

FIGS. 5 and 6 illustrate respectively schematic front and side elevational views of a base member (shown also in FIGS. 1 and 2) that is interposed between the pedestal turntable and the other supporting structure of the boom;

FIGS. 7 and 8 illustrate respectively side and front elevational views of a sector gear or boom support structure that is shown also in FIGS. 1 and 2. This support structure is pivotally connected to the base member that is shown separately in FIGS. 5 and 6, and the reciprocable boom shown in FIGS. 1 and 2 is mounted to this gear.

Referring now to the drawing, the numeral 11 designates the main frame of a vehicle that has front and rear wheels 13, 15. The frame of this particular vehicle is articulated, having a front portion 17 and a rear portion 19. The front and rear portions 17, 19 are pivotally connected to each other by ball and socket arrangements 21, and steering is effected by the rotational engagement of a pinion (not shown) with a sector gear 23. To provide operational stability, a plurality of outriggers 25 are connected to the frame of the machine. These outriggers are lowered to engage the ground when the machine reaches the location at which it is to operate. It should be initially noted that my invention need not necessarily be applied to vehicular bodies, but may be applied to stationary objects, such as loading platforms and the like. The vehicular arrangement shown, however, is selected for illustration and description since it is a common practice to mount cranes to mobile supports.

Upon the rear portion 19 of the frame is a pedestal turntable 27 that rotates about a substantially vertical axis. The construction of the turntable may be seen in better detail in FIGS. 3 and 4. A post 29 is secured to the rear' portion 19 of the frame and has a ball 31 secured to the upper end thereof. A socket arrangement 33 encompasses the ball 31 and is secured to a housing 35 (shown here as pyramidal shaped) that encompasses the post 29. The lower end of the housing 35 is secured to a cylindrical base plate 37 that encloses a gear 39 that is secured to the rear portion 19 of the vehicle frame. An electric gear motor having an output pinion 41 is secured to the cylindrical base plate 37 and extends therethrough to engage the gear 39 to rotate the housing 35 of pedestal turntable 27.

At the upper end of the pedestal turntable 27 are a pair of protrusions 43 that have aligned apertures therein for receiving the extremities 45 of base member 47. Base member 47 has parallel extending legs 49, 51 and the lower legs 51 have extremities 53 (see FIGS. 5 and 6) that mate with apertured protrusions 55 on the pedestal turntable. A removable pin 46 is inserted into the apertures of protrusions 43 of the pedestal turntable and through the apertured extremities 45 of the base member 47. Another pin 48 is inserted into the apertures of protrusions 55 of the turntable and through the aperture of extremities 53 of base member 47. When the upper pin 46 is removed, the base member 47 can rotate about lower pin 48 to the position shown in FIG. 2. This is advantageous since the machine illustrated is quite large and its overall height should be decreased to facilitate transportation of the machine from one location to the other, particularly if the distances between locations are large.

An upper end of the base member 47 has a protrusion 56 upon which is mounted an electric gear motor having an output pinion 57. It should be understood that the shape of the base member 47 is not restricted to the configuration shown nor is the scope of my invention limited to the use of the pedestal turntable 27. Rather, the turntable 27, frame 11 and base member 47 constitute a base that may be conveniently used to support the apparatus described below.

Pivotally secured to the base member 47 is a sector gear or boom support structure 59. The preferred means selected to effect the pivotal connection are ball and socket arrangements 62, the balls 63 of which are clearly visible in FIGS. 7 and 8 and the sockets 64 of which are shown in FIGS. and 6. As may be noted in connection with FIG. 7, the sector gear 59 has'an inner region A and an outer region B. The inner region A supports the ball arrangements 63 and the outer region B includes a gear portion 61. As shown, the sector gear 59 is preferably enlarged below the geared portion 61 and includes an elongated aperture 66 into which is inserted a reciprocable boom 65. A rack 67 is formed to extend longitudinally along the lower edge of the boom 65 and is adapted to engage the output pinion 69 of an electric gear motor that may be seen clearly in FIG. 8. Thus, the driving of the pinion 69 enables the extension or retraction of the boom 65. The boom 65 is supported by bearings 68, 70, each of which has a plurality of rollers 72 that engage longitudinally extending flanges 74 on the boom.

The output pinion 57, which is mounted to the base member 47 (see especially FIG. 5), engages the toothed portion 61 of sector gear 59 to control the attitude of the boom 65. A grapple 75 is included on one extremity of the boom for lifting purposes, but other lifting devices are Within the scope of the invention.

In operation, the frame 11 of the vehicle is transported to a selected location and the Outriggers 25 are lowered to provide stability. The pinion 41 (see FIG. 4) that engages the gear 39 of the pedestal turntable 27 is driven so that the boom 65 is moved into a selected vertical plane. Then the output pinion 57 (see FIG. 5) on base member 47 is driven to adjust the attitude of boom 65. Then the boom 65 is reciprocated to a selected position by driving the output pinion 69 on the sector gear or boom support structure 59. If an article that is close to the frame 11 of the vehicle is to be lifted, the construction of the boom 65 enables the grapple 75 to be moved very close to the vehicle. This position is shown in phantom in FIG. 1. To lift the article, the output pinion 57 is driven so that the sector gear or boom support structure 59 is rotated in a clockwise direction. If the article lifted is to be moved outwardly to a point on the same level as the gound, the boom 65 is extended by driving the output pinion 63. Then, the pinion 57 of base member 47 is driven to lower the boom 65. And, as stated previously, the article may be positioned in any selected vertical plane by driving the pinion 41 that rotates the pedestal turntable 27.

It should be apparent from the foregoing that I have provided an improved boom type crane having significant advantages. Of particular importance is the advantage achieved by having a boom support structure 59' with a pivot point 62 located at an inner region of the support structure and thus away from the boom 65. This arrangement permits articles to be lifted to a high elevation while keeping the distance from the end of the boom 65 or the grapple 75 to the support 68 of the boom to a minimum. As is apparent in FIG. 1, the boom 65 may be retracted to the position shown in phantom. Thus, the stresses in the boom are minimized and heavier articles may be lifted by the crane.

Another advantage derives from the fact that the boom is reciprocably mounted to the boom support structure. This enables the grapple 69 to .be moved extremely close to the boom support structure 66 in a convenient manner, enables a further deduction in the stresses of the beam, and enables the lifting of larger and heavier articles without danger of overstressing the boom.

Another advantage is that the attachment of the boom to an outer region of a boom support structure that i1 turn is connected at an inner region to a base enables the use of apparatus which engages the boom support structure at the outer region thereof to pivot the support structure. Consequently, the power means operates at a large distance from the point of pivotal connection of the boom support structure and the base and, therefore, the force required to pivotally move the boom with respect to its supporting base is decreased.

While I have shown my invention in only one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes with out departing from the spirit thereof.

I claim:

1. A crane which comprises:

(a) a frame;

(b) a pedestal turntable mounted on said frame to rotate about a substantially vertical axis;

(c) a base member connected to and extending upwardly and outwardly from connection means joining said pedestal turntable;

(d) a boom support structure having an inner region and an outer region;

(e) means pivotally mounting said boom support structure at its inner region on said base member for movement about a substantially horizontal axis;

(f) a boom;

(g) means on said boom support structure at the outer region thereof for supporting said boom for reciprocable movement (h) power means engaging said boom to reciprocate the boom; and

(i) power means engaging said boom support structure at the outer region thereof to pivot said support structure about said horizontal axis.

2. The invention as defined by claim 1, wherein the means connecting said base member and said pedestal turntable enables pivotal movement of said base member inwardly toward said frame to decrease the overall height of the crane to facilitate transportation.

3. The invention as defined by claim 1, wherein said boom has a rack that extends longitudinally thereof, and is driven by the output pinion of a gear motor which is mounted on the boom support structure.

References Cited UNITED STATES PATENTS HUGO O. SCI-IULZ, Primary Examiner. 

